Messy commute in SR 99 tunnel includes traffic and exhaust fumes

Drivers got their first taste of a messy commute inside the new SR 99 Tunnel Wednesday morning.

Cars were backed up in tight quarters, and some drivers complained of exhaust fumes in the air.

The Washington State Department of Transportation (WSDOT) confirms their crews smelled the exhaust fumes as well, so they manually turned on the tunnel’s ventilation system. The tunnel naturally clears air as traffic travels through, but several 500 horsepower fans activate during times of congestion.

WSDOT says they will monitor that smell moving forward. As for the traffic, they expect the adjustment period to continue as commuters test out the new route.

“We expect to see people continue to try it out,” WSDOT Spokesperson Bart Treece said. “It’s a little bit of a learning curve, so we’ll continue to see that happen.”

WSDOT and the Seattle Department of Transportation will be closely monitoring traffic conditions and making adjustments where they see fit. Several changes are already in the works.

WSDOT is in the process of installing traffic meters along the on-ramps on both sides of the tunnel. They also plan to open an off-ramp at Dearborn Street in the coming weeks.

Surface streets will see changes, too. Ten intersections around the tunnel uses an “Intelligent Traffic Control System” that can automatically adjust traffic signals based on congestion. SDOT says right now the system is just studying these early commutes before it makes changes to help traffic flow.